Dogs & Caves
Diana Tomchick
- NEWS
Who let the wolves in? Genetic record for domestic dogs pushed back by 5,000 years
Dogs were early man’s best friend. A pair of Nature papers published today have identified the oldest dog genomes on record in remains from archaeological sites spanning Europe and the Middle East1,2.
The remains, from the United Kingdom, Switzerland and Turkey, are 14,000 to 16,000 years old and push the genetic record for dogs back by more than 5,000 years. They also identify an early domestic dog population (Canis lupus familiaris) that spanned Western Eurasia and was kept by diverse human hunter-gatherer groups. The animals’ genetic signature is still present in dogs today.
The studies do not pinpoint where, when and why dogs were first domesticated by humans, but some researchers say they narrow down the search. The studies also show that dogs were exported and exchanged by various human groups, underlying dogs’ importance to early communities with different ways of living.
“Every time people move, they take their dogs with them,” says Lachie Scarsbrook, an evolutionary geneticist at the Ludwig Maximilian University (LMU) of Munich in Germany, and a co-author of one study. “We call it the Swiss army dog. They can adapt to all these cultural roles.”
Social animals
Humans domesticated dogs from an ice-age population of grey wolves (Canis lupus). But despite decades of intense archaeological and genetic study, scientists still don’t know when or where, let alone why, this occurred.
Part of the challenge has been discerning domestic dogs from wolves when the remains are often fragmentary: bones as old as 30,000 years had been linked to domestic dogs on the basis of their shape, only for DNA sequencing to confirm them as being those of wolves. Before the latest studies, the oldest dog DNA came from fossils nearly 11,000 years old, from northwest Russia3.
To push this record back further, a team led by researchers at the LMU and the Natural History Museum (NHM) in London generated genome sequences from suspected dog remains from Gough’s Cave, in Cheddar Gorge in southwest England, and highly fragmented bone — resembling freeze-dried coffee, says Scarsbrook — from a Turkish site called Pınarbaşı.
Sequencing confirmed that the sample from Pınarbaşı, dated to 15,800 years ago and determined to be from a female puppy on the basis of teeth, and the 14,300-year-old Gough’s Cave remains were clearly those of domestic dogs. The genomes were remarkably similar, pointing to the rapid spread of domestic dogs across Europe and western Asia, the researchers say.
Although the humans associated with these two early dogs were both groups of ice-age hunter-gatherers, they were strikingly different, says co-author William Marsh, a palaeogeneticist at the NHM. At Pınarbaşı, humans also depended on fishing and small birds, whereas the humans at Gough’s Cave would have been terrestrial hunters.
Despite these differences, both groups treated the remains of their dogs as they did human remains. The skull of the Gough’s cave dog contained decorative perforations, not dissimilar to the modifications made to human skulls at the site, which are thought to be associated with ritual cannibalism. In Pınarbaşı, dog remains were intentionally buried atop deceased humans. Isotopic evidence suggests that the dogs at both sites ate the same foods as humans. “Four thousand kilometres apart, we see these dogs being treated in very similar ways,” Marsh says.
Asian origins?
The second team, led by researchers at the Francis Crick Institute in London, identified another very early dog after screening hundreds of suspected dog and wolf remains. Using a technique that has supercharged ancient human genomics, in which ancient DNA is ‘captured’ among microbial contaminants, the researchers were able to discern dog from wolf in more than 130 samples. They identified 14 dogs that lived among hunter-gatherers in Europe, including a 14,200-year-old sample from a Swiss site called Kesslerloch.
The genetic signature of these early European dogs was surprisingly resilient, the researchers found, persisting through the arrival of Middle Eastern farmers and dogs and into present-day European dog breeds, such as German shepherds. “The dogs don’t seem to care too much which culture they’re attached to,” says Adam Boyko, a canine geneticist at Cornell University in Ithaca, New York.
An unpublished preliminary analysis by Marsh – who has joined the team at The Crick – found that the Kesslerloch sample is closely related to the Gough’s cave dog remains, and that both have nearly identical mitochondrial DNA sequences to the Pınarbaşı dog. The three dogs were probably part of a single ice-age population that spanned Europe and the Middle East, says Ludovic Orlando, a palaeogeneticist at the University of Toulouse in France. “That was unknown. That is a big discovery,” he says.
Orlando thinks the two studies shed little light on the origins of dog domestication, but he is hopeful that the DNA-capture approach developed by the Crick team will mean that poorly preserved samples that pre-date the latest finds become amenable to sequencing.
Boyko thinks the two studies, along with other evidence, point to the first domesticated dogs originating somewhere in Asia. A 2022 study found that ancient and modern dogs are more closely related to ice-age wolves from Asia than European wolves4, whereas Boyko’s own work has found that ‘village dogs’ in central Asia are a centre of modern dog diversity5.
It’s looking unlikely that dogs were first domesticated in Europe, says Anders Bergström, an evolutionary geneticist at the University of East Anglia in Norwich, UK, and co-author of the study that analysed the Kesslerloch remains. A previous study proposed that dogs were domesticated independently in Europe and Asia from two local wolf populations6, but both teams involved in the latest studies found that the earliest European dogs were related to Asian wolves. “Probably we are instead looking towards Asia, but Asia is a very big place,” says Bergström.
Professor
Departments of Biophysics and Biochemistry
UT Southwestern Medical Center
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